This invention relates to a closed loop function selector valve which selectively directs hydraulic fluid pressure to any one of several hydraulic related devices wherein the low pressure drain or return of each of the connected devices is directed back through the valve.
Known prior methods of directing hydraulic pressure to several hydraulic devices typically involved a combination of spool and shut-off style valves. For ease of illustration and understanding, the prior art and this invention will be explained as used in a tilting bathtub for invalid care. It should be understood that application of the present invention is for illustration purposes not exclusive for such use as there may be many applications for this unique valve. Tilting bath tubs, as described in this nonexclusive valve application, may be viewed in detail in U.S Pat. Nos. 3,174,160; 3,924,278; 4,207,629; 2,536,540; 2,541,263; 3,889,304; and 3,827087.
The functional operation of such tilting bath tubs may readily be powered by ordinary or household water line pressure which may range from 40 to 80 pounds per square inch (psi). Such functions may include tilting the empty tub forward for loading the invalid; tilting the tub backward to a horizontal bathing position; opening the tub drain to permit water tempering; tempering the tub water with the combination of cold and hot water lines; closing the tub drain; filling the tub with tempered bath water; opening the tub drain; and tilting the empty tub forward to facilitate the invalid's exit from the tub.
Referring to FIG. 1, known prior methods to perform these hydraulically activated functions or operations would require four valves--two spools 28, 36 and two shut-off valves 44, 48.
Hydraulic fluid pressure with continuous line pressure to each valve is derived from household cold water line 10 and hot water line 12 which are directed into mixing valve 14 which has a cold water input 16 and a hot water input 18 and a mixed or tempered water output 20. The tempered water is then directed through thermometer manifold 22 through mixed input 24 wherein the temperature is measured to assure the proper operation of the mixing valve 14. The mixed output 26 of thermometer manifold 22 is then directed or is in flow communication with tilt spool valve 28, drain spool valve 36, temper shut-off valve 44, and fill shut-off valve 48.
Tilt spool valve 28 has a pressure input 30 and a release output 32, which are reversible, connected to lift cylinder 34. Drain spool valve 36, which includes reversible pressure input 38 and release output 40, is connected to drain cylinder 42. Temper shut-off valve 44 is in flow communication with drain 46. Fill shut-off valve 48 is directed to tub 50. By this arrangement, the above mentioned functions may be performed with the combination of these four valves and hydraulic fluid or conventional water line pressure.
Referring to FIG. 2, the present invention is schematically shown in a similar application as the known prior arrangement shown in FIG. 1. Cold water line 10 and hot water line 12 are connected to the cold input 16 and hot input 18 of mixing valve 14 with mixed output 20. The mixed output 20 is directed through thermometer manifold 22 via mixed input 24 afterwhich it leaves manifold 22 through mixed output 26 directed solely to valve high pressure line input port 92 of closed loop function selector valve 60 which in turn directs the high pressure fluid or water to any of the following: forward tilt function port 80; backward tilt function port 82; open drain function port 84; temper water function port 86; closed drain function port 88 or fill tub function port 90. Such function ports are respectively in flow communication with the lift cylinder 34, drain cylinder 42, drain 46 and bathtub reservoir 50.